Execute Brain****/Ruby

From Rosetta Code
Execute Brain****/Ruby is an implementation of Brainf***. Other implementations of Brainf***.
Execute Brain****/Ruby is part of RCBF. You may find other members of RCBF at Category:RCBF.

Version 1[edit]

An implementation of a Brainf*** interpreter in Ruby. More effort could be made to read a program from a file or from stdin.

class RCBF
def initialize(program)
@d = [0] * 30_000
@program = program
@jumpback_table = read_program
end
 
def read_program
jumpback_table = {}
jump_to = []
@program.each_char.with_index do |char, idx|
case char
when "[" then jump_to.push(idx)
when "]" then jumpback_table[idx] = jump_to.pop
end
end
jumpback_table
end
 
def run
invert_table = @jumpback_table.invert
dc = 0
pc = 0
while pc < @program.length
print [pc, @program[pc]] if $DEBUG
 
case @program[pc]
when ?>
dc += 1
print "\t#{dc}" if $DEBUG
when ?<
dc -= 1
print "\t#{dc}" if $DEBUG
when ?+
@d[dc] += 1
print "\t#{dc},#{@d[dc]}" if $DEBUG
when ?-
@d[dc] -= 1
print "\t#{dc},#{@d[dc]}" if $DEBUG
when ?.
print "\t#{dc},#{@d[dc]}\t" if $DEBUG
print @d[dc].chr
when ?,
@d[dc] = $stdin.getc
print "\t#{dc},#{@d[dc]}" if $DEBUG
when ?[
if @d[dc] == 0
pc = invert_table[pc]
print " #{[pc,@program[pc]]}" if $DEBUG
end
when ?]
if @d[dc] != 0
pc = @jumpback_table[pc]
print " #{[pc,@program[pc]]}" if $DEBUG
end
end
puts if $DEBUG
pc += 1
end
end
end
 
# output 'Hello World!\n'
helloworld = <<PROGRAM
++++++++++[>+++++++>++++++++++>+++>+<<<<-]
>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>.
PROGRAM

bf = RCBF.new(helloworld)
bf.run
 
# use nested loop to increment count to 64 and print (should be '@')
# followed by a newline
RCBF.new('>>++++[<++++[<++++>-]>-]<<.[-]++++++++++.').run
Output:
Hello World!
@

Version 2[edit]

This variant converts the brainfuck into Ruby code and runs that instead. Do note that this requires Ruby1.9.1 or later, earlier versions need a somewhat more verbose variant.

BF code may be read from a file or taken from STDIN.

eval 'm=Hash.new(p=0);'+ARGF.read.gsub(
/./,
'>' => 'p+=1;',
'<' => 'p-=1;',
'+' => 'm[p]+=1;',
'-' => 'm[p]-=1;',
'[' => '(;',
']' => ')while((m[p]&=255)!=0);',
'.' => 'putc(m[p]&=255);',
',' => 'm[p]=STDIN.getc.ord if !STDIN.eof;')